Multiple chamber pacing is becoming a common therapeutic method for extending the life of patients with particular cardiac deficiencies. In order to achieve multiple chamber pacing, two or more leads are inserted into the same vein. As a result of leadwires residing in the various vessels, these patients may develop partial venous thrombosis. This occlusion can potentially stop the blood supply and become life-threatening. Additionally, narrowing of vessels due to fibrosis, secondary to remnant pacemaker leadwires, can cause death. Smaller diameter leadwires will promote less occlusion of the vein than larger diameter wires. Using techniques developed for computer hard drive fabrication, we will produce a micro-stimulation leadwire, quantify its fatigue life relative to a reference test coil, and statistically qualify its efficaciousness for cardiac pacing. We expect our leadwire to be 3 French in diameter, approximately 60% smaller than bipolar leads available today. PROPOSED COMMERCIAL APPLICATIONS: The total arrhythmia management market was forecasted to exceed $4.5 billion last year. This market includes bradycardia implants, implantable cardioverter defibrillators (ICD), and external automated defibrillators. Specifically, in 1998 the forecast for bradycardial pacemaker implants exceeded 540,000 units worldwide, resulting in $2.6 billion in sales. With a growth rate of 26%, the ICD market is expected to surpass the bradycardial implant market by the year 2004. Dual chamber pacing devices are expected to be the main driver of growth in this market (l8).